Embodiments of the present invention apply, in particular, to an ore crusher, the drum then being adapted to receive an ore to be crushed.
A rotary drum apparatus of aforementioned type is described in U.S. Pat. No. 3,555,329. This apparatus is a cement mill comprising a drum around a longitudinal axis and a motor for driving the drum in rotation around the longitudinal axis. The motor comprises a rotor joined together with the drum, and a stator having a stator winding. The stator winding is adapted to generate a magnetic field driving the rotor in rotation.
The stator is in the form of a revolution ring around the longitudinal axis. The stator surrounds perpendicular to the longitudinal axis, the rotor which is itself fixed to the periphery of the drum along a plane perpendicular to the longitudinal axis. The stator then extends against the entire circumference of the drum along a plane perpendicular to the longitudinal axis.
However, such a rotary drum apparatus has reliability problems related to mechanical vibrations of the drum and associated mechanical deformations. The drum can have high-value diameter, generally between 5 meters and 12 meters, along the plane perpendicular to the longitudinal axis. This leads to significant operating losses when the drive motor is damaged and must be stopped in order to be repaired.